Just in case it helps anyone else, I found out why I was having such a hard time getting Old NuPIC to pass tests on Mac OS/X.
The docs suggest to run tests like this:
$ py.test tests/unit
For some reason, py.test will use it’s own Python library paths, ignoring the paths you’ve defined that are working for everything else.
Try this small change, instead:
$ python -m pytest tests/unit
Now the correct paths are used, and tests pass easily. Thanks.